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Nitrogen fertilisation reduces sink strength of poplar ectomycorrhizae during recovery after drought more than phosphorus fertilisation.

Plant Soil 419, 405–422 (2017)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Background and aims: Drought reduces the carbon (C) flux from leaves (source) to mycorrhizal roots (sink); however, during recovery from drought, C flux exceeds the levels observed in irrigated controls. This process could be source- or sink-controlled. We studied this source–sink relationship in an agronomically used poplar clone grown at different levels of nitrogen (N) and phosphorus (P) fertilisation as used in silvoarable agroforestry systems. Methods: We conducted a fully factorial pot experiment combining four fertiliser and two drought regimes. Gas exchange and chlorophyll and flavonol indices were regularly monitored. One week after rewatering, we performed 13 CO 2 pulse labelling. At harvest, enzyme activities of ectomycorrhizal root tips were determined. Results: After one week of recovery, we observed an excess in C allocation to ectomycorrhizae (ECM) in non-N-fertilised treatments. However, net photosynthesis only recovered to the level of continuously irrigated controls. Drought increased chitinase, cellulase, phosphatase and peptidase activities, but the latter only in N-fertilised treatments. Conclusions: We add evidence that the allocation of recently assimilated C is most likely sink-controlled. Less C allocation to recovering ECM supplied with fertiliser may be either due to better nutritional status and hence higher stress tolerance, or due to partitioning between above and below-ground sinks.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords 13 C ; Drought Stress ; Ectomycorrhizae ; Poplar ; Recovery; Water-use Efficiency; Arbuscular-mycorrhizal Fungi; Sphaerosporella-brunnea; Carbon Allocation; Stomatal Control; Plant-cells; Clear-cut; Stress; Growth; Soil
ISSN (print) / ISBN 0032-079X
e-ISSN 1573-5036
Journal Plant and Soil
Quellenangaben Volume: 419, Issue: 1-2, Pages: 405–422 Article Number: , Supplement: ,
Publisher Springer
Publishing Place Dordrecht
Non-patent literature Publications
Reviewing status Peer reviewed